A file tray is commonly used for receiving, storing, sorting or organizing files, documents, mails, . . . etc. A simple file tray can be an open-top box made of metal, wood, plastic or paperboard. A disadvantage of such a file tray with a permanent structure is that it must occupy an equal space during usage and non-usage (ie., transportation or storage.) Another disadvantage is that it normally requires additional means of support to stack up to each other.
In some applications, multiple file trays are constructed within a structure, which is divided into a fixed number of rows and columns of trays by internal partitions. The disadvantage of such arrangement is that user can not alter the size of entire structure or the number of trays for usage.
The present invention is directed to a one piece, cut and scored paperboard blank so that it is ready to be folded into a folder type file tray. Therefore, it can be flattened to a reduced size during transportation and storage. The present invention is also directed to the structure of file tray so that individual file tray can be directly stacked up to each other without additional means of support.
Various styles and shapes of folder type paperboard boxes have been disclosed in the prior art for usage in packaging, food and beverage industries. For example, U.S. Pat. No. 5,839,649 disclosed a trapezoidal paper box with inner partitions made from a single paperboard blank. U.S. Pat. No. 5,183,200 disclosed a folder type paper box that can be assembled by bonding only one face in assembly. U.S. Pat. No. 4,109,786 disclosed a folder type paper box to hold round cylindrical articles in an angular position. U.S. Pat. No. 3,935,992 disclosed a folder type paper box with dual functions of a container and an open receptacle. U.S. Pat. No. 2,237,706 disclosed a display basket for toilet articles made from a single paperboard blank. However, none of prior art of folder type paper box can serve the unique purpose of the file tray of present invention.